P2191
Universal (All Makes) Vehicle (OBD-II)
Severity:What Does This Error Mean?
P2191 means the fuel system is too lean at higher engine loads on Bank 1. Unlike P2187 (lean at idle), P2191 sets when the lean condition occurs during acceleration or load conditions. This means the engine is not getting enough fuel when it needs it most. Symptoms include hesitation, stumble, or surging during acceleration. Fuel delivery problems — weak pump, restricted injectors, or high fuel pressure drop under load — are common causes.
Affected Models
- Common in VW Golf, Jetta, and Passat with direct injection
- Common in Audi A3 and A4 with FSI/TFSI engines
- Seen in turbocharged Ford EcoBoost engines under boost
- Also appears on naturally aspirated engines with fuel delivery issues
Common Causes
- Weak fuel pump unable to maintain adequate pressure during high-load acceleration
- Restricted or clogged fuel filter reducing flow under high demand
- Partially clogged fuel injectors not delivering full fuel volume at wide-open throttle
- Faulty fuel pressure regulator allowing pressure to drop excessively under load
- High-pressure fuel pump failure on direct injection engines — common on VW/Audi TFSI engines
How to Fix It
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Note whether the hesitation or stumble occurs during acceleration or under load — P2191 is a load-related lean code.
A lean condition only under acceleration points to fuel delivery capacity, not idle vacuum leaks.
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Check fuel pressure at idle and during a snap throttle test. Pressure should remain stable — a significant drop under load indicates pump weakness.
A fuel pressure drop of more than 5 PSI during snap throttle suggests the pump cannot keep up with fuel demand.
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Replace the fuel filter if it has not been changed recently. A clogged filter restricts flow under high demand even when idle pressure seems fine.
On vehicles with a maintenance fuel filter, replacement every 30,000 miles is recommended.
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Have the fuel injectors professionally flow-tested or use a fuel system cleaner in the tank as a first step.
Partially clogged injectors deliver less fuel per pulse — you notice this most during high-load acceleration.
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On VW/Audi direct injection engines, inspect the high-pressure fuel pump and camshaft follower (pump follower) for wear.
The cam follower that drives the high-pressure pump on 2.0T FSI/TFSI engines is a well-known wear item that causes lean codes.
When to Call a Professional
Fuel filter replacement is $30 to $80 — should be done as a first step. Fuel pump replacement is $200 to $700 depending on the vehicle. High-pressure fuel pump on VW/Audi direct injection is $200 to $500 in parts plus labor. Fuel injector cleaning service is $50 to $150 at a shop.
Frequently Asked Questions
What is the difference between P2187 and P2191?
P2187 is lean specifically at idle — low load conditions. P2191 is lean during higher load — acceleration, climbing a hill, or highway passing. P2187 points to air leaks and idle fuel delivery issues. P2191 points to fuel delivery capacity problems — the system cannot keep up with high demand.
Can a dirty air filter cause P2191?
A severely clogged air filter can restrict airflow enough to affect performance. However, a dirty filter typically causes rich conditions (not lean) because it restricts air more than fuel. P2191 is more likely caused by insufficient fuel delivery rather than air restriction.
Is P2191 common on turbocharged engines?
Yes — turbocharged engines demand significantly more fuel under boost pressure. If the fuel system cannot keep up with the increased demand under boost, lean conditions develop. VW/Audi 2.0T engines are particularly well known for high-pressure fuel pump failures causing P2191.